Question

Why did the Great Compromise and the Three-Fifths Compromise involve so much debate and discussion at the Constitutional Convention?

Answer 1

Because each state was paying special mind to its own advantages as to portrayal in Congress:

1. The Great Compromise and the Three-Fifths Compromise both concentrated on  the portrayal of states in Congress. Both of these trade offs were concocted amid the United States Constitutional Convention in 1787.  
2. The Great Compromise settled a debate between little populace states and extensive populace states. The substantial populace states needed portrayal in Congress to be founded on a state's populace measure. The littler states dreaded this would prompt unchecked strength by the huge states; they needed all states to get a similar measure of portrayal. The Great Compromise made a bicameral (two-chamber) governing body. Portrayal in the House of Representatives would be founded on populace. In the Senate, all states would have a similar measure of portrayal, by two Senators.  
3. The Three-Fifths Compromise was a method for bookkeeping (to some degree) for the number of inhabitants in slaves in states that allowed bondage. For tax collection and portrayal purposes, the inquiry was whether slaves should check in the populace figures. (They were not viewed as casting a ballot subjects around then.)   The Three-Fifths Compromise said that three out of each five slaves could be tallied while deciding a state's populace estimate for deciding what number of seats that state would get in the House of Representatives.

Answer 2

When it came to the representation of the Congress there was a lot of discussion and debate at the Convention.

Both of the states were caught up in their own needs and interests. The Three-fifths and the Great compromise focused greatly on how to reperesent themselves at the Congress.

It was in 1787 that these were devised by the Constitutional Convention of the United States.